Numerical Simulation of Cu（In,Ga）Se2 Solar Cells Performances

This paper presents a numerical characterization of copper-indium-gallium-diselenide thin film solar cells using one dimensional simulation program （SCAPS-1D）. We have performedan optimization of the performances of the standard Mo/Cu（In, Ga）Se2/CdS/ZnO solar cells using current-voltage and quantum efficiency methods. With a CuIn..7Ga0.3Se2 absorber, we have investigated the buffer layer thickness, temperature, series and shunt resistances effects on the open-circuit voltage, short-circuit current density, fill factor, conversion efficiency and quantum efficiency. The simulated results show good performances when the thickness of the buffer layer is in the range of 10-40 um due to the reduction of absorption in the short wavelenghts （380-500 nm）. High performances of the model is obtained when the series and shunt resistances is in the range of 0.1-1 Ω·cm^2 and 1,000 Ω·cm^2, respectively. Under these conditions, the cell can theoretically operate under an ambiant temperature of 370 K without any loss of its performances.

Effect of Strontium on Structure and Superficial Area of La_(2)O_(3)

Recently, lanthanum oxide doped by group IIA elements may strongly influence solid state reaction. A series of samples, noted LaSrX (where X = % atomic of strontium) have been prepared by hydrolysis, in neutral medium from La2O3 and SrCO3. These samples were calcined under air at 450?C and 1150?C then characterized by specific surface area (BET), X-ray diffraction, scanning electron microscopy (SEM), thermogravimetry (TG) and differential thermal analysis (DTA). Obtained results show that after calcinations at: 1) 450?C, the addition of strontium is without effect on surface of La2O3 and the XRD analysis revealed no interaction between lanthanum oxide and strontium carbonate;2) 1150?C, the sintering of the samples is very important, reduction of 70% of surfaces compared to the samples calcined at 450?C;XRD results show that LaSrX are formed principally by two oxides: SrLa2O4 and La2O3, which is confirmed by SEM method. The reaction between La2O3 and SrCO3 showed three endothermic weight losses;elimination of water, a partial dehydroxylation of La(OH)3 and formation of La2O2CO3 and La2(CO3)3.

Statistical Study of foF2 Diurnal Variation at Dakar Station from 1971 to 1996:Effect of Geomagnetic Classes of Activity on Seasonal Variation at Solar Minimum and Maximum

The statistical study of F2 layer critical frequency at Dakar station from 1971 to 1996 is carried out. This paper shows foF2 statistical diurnal for all geomagnetic activities and all seasons and that during solar maximum and minimum phases. It emerges that foF2 diurnal variation graphs at Dakar station exhibits the different types of foF2 profiles in African EIA regions. The type of profile depends on solar activity, season and solar phase. During solar minimum and under quiet time condition, data show?the signature of a strength electrojet that is coupled with intense counter electrojet in the afternoon. Under disturbed conditions,?mean intense electrojet is observed in winter?during fluctuating and recurrent activities. Intense counter electrojet is seen under fluctuating and shock activities in all seasons coupled with strength electrojet in autumn. In summer?and spring under all geomagnetic activity condition, there is intense counter electrojet. During solar maximum, in summer and spring there is no electrojet under geomagnetic activity conditions.?Winter shows a mean intense electrojet. Winter and autumn are marked by the signature of the reversal electric field.